1. Field of the Invention
The present invention relates to an exhaust treatment unit for treating exhaust gas from an engine of a work vehicle, a manufacturing method of the exhaust treatment unit, and a work vehicle equipped with the exhaust treatment unit
2. Background Information
Work vehicles such as a hydraulic excavator are equipped with an exhaust treatment device. The exhaust treatment device is connected to an engine through a connection pipe in order to treat the exhaust gas from the engine. The exhaust treatment device includes a diesel particulate filter (DPF) device and a selective catalytic reduction (SCR) device. The diesel particulate filter device reduces particulates contained in the exhaust gas. The selective catalytic reduction device reduces nitrogen oxide (NOx) contained in the exhaust gas. In some cases, these two exhaust treatment devices are disposed in a single unit for facilitating maintenance, and the unit is installed in a work vehicle. Such unit is referred to as an exhaust treatment unit.
When the exhaust treatment unit is attached to the engine such that the exhaust treatment unit is supported by the engine, such heavy product is designed to be disposed on the upper part of the engine. Therefore, large load for attaching the exhaust treatment unit to the engine acts on a bracket. When enlarged for a reinforcement purpose, the bracket is inevitably increased in its weight.
Therefore, it is preferable to attach the exhaust treatment unit to a support member other than the engine. For example, in Japan Laid-open Patent Application Publication No. JP-2012-097413(A), a table is mounted on an upper frame through support legs. The diesel particulate filter device and the selective catalytic reduction device are disposed on the top surface of the table.
Specifically, the table is mounted on support legs, each of which is composed of many components. The diesel particulate filter device is disposed either directly on the table or on a separately provided mount part disposed on the table. The selective catalytic reduction device is disposed on the separately provided mount part disposed on the table. Alternatively, a hanger bracket is disposed above the table instead of the mount part, and the diesel particulate filter device and the selective catalytic reduction device are hung from the hanger bracket.
In the invention according to Japan Laid-open Patent Application Publication No. JP-2012-097413(A), either the hanger bracket or the mount part, which is separately provided from the table, is provided for fixing the diesel particulate filter device and the selective catalytic reduction device. Therefore, the number of components of the exhaust treatment unit is increased. This causes drawbacks of an increase of manufacturing cost and a time-consuming assembling work.
It is an aim of the present invention to provide an exhaust treatment unit, a manufacturing method of the exhaust treatment unit, and a work vehicle, whereby a diesel particulate filter device and a selective catalytic reduction device can be stably supported with a small number of components.
An exhaust treatment unit according to a first aspect of the present invention is for treating exhaust gas from an engine of a work vehicle, and comprises a first exhaust treatment device, a second exhaust treatment device and a first bracket. The first exhaust treatment device and the second exhaust treatment device are attached to the first bracket. The first bracket includes a brim part and a main body part. The main body part has a convex shape downwardly bulged from the brim part. The main body part includes a first support portion and a second support portion. The first support portion directly supports the first exhaust treatment device. The second support portion directly supports the second exhaust treatment device.
The main body part may include a first attachment portion, which allows a hoist hook to be attached thereto, on a lateral surface thereof.
The main body part may further include a first bulged portion and a second bulged portion. The first bulged portion is bulged further downward than the first support portion in a position located under the first exhaust treatment device except for the first support portion. The second bulged portion is bulged further downward than the second support portion in a position located under the second exhaust treatment device except for the second support portion.
The main body part may further include a rib upwardly protruded between the first bulged portion and the second bulged portion.
The first support portion may be positioned below the second support portion.
The aforementioned exhaust treatment unit further may comprise a relay connection pipe connecting the first exhaust treatment device and the second exhaust treatment device. The relay connection pipe may be disposed above the first exhaust treatment device and the second exhaust treatment device.
The first support portion may include a contact surface fitted to an outer peripheral surface of the first exhaust treatment device. Additionally, the second support portion may include a contact surface fitted to an outer peripheral surface of the second exhaust treatment device.
The first exhaust treatment device and the second exhaust treatment device may have cylindrical shapes. Moreover, the first support portion and the second support portion may have arc-shaped cross-sections.
The aforementioned exhaust treatment unit may further comprise a first U-shaped bolt locking the first exhaust treatment device. And the main body part may further include a second attachment portion to which the first U-shaped bolt is attached and which is provided on the both sides of the first support portion in a direction perpendicular to a center axis of the first exhaust treatment device.
The aforementioned exhaust treatment unit may further include a second U-shaped bolt locking the second exhaust treatment device. And the main body part may further include a third attachment portion to which the second U-shaped bolt is attached and which is provided on the both sides of the second support portion in a direction perpendicular to a center axis of the second exhaust treatment device.
The aforementioned exhaust treatment unit may further include a first reinforcement plate. The first reinforcement plate may contact the second attachment portion on a surface of the main body part, the surface being opposite to the other surface of the main body part where the first exhaust treatment device and the second exhaust treatment device are supported.
The aforementioned exhaust treatment unit may further include a second reinforcement plate. The second reinforcement plate may contact the third attachment portion on a surface of the main body part, the surface being opposite to the other surface of the main body part where the first exhaust treatment device and the second exhaust treatment device are supported.
The first exhaust treatment device may include a connection port downwardly extended in a tubular shape. In addition, the main body part may further include a first hole portion through which the connection port is inserted.
The main body part may further include a second hole portion for dropping a foreign object therethrough in at least either of the first bulged portion and the second bulged portion.
In a plan view, a maximum width of the first bulged portion in a first direction perpendicular to a longitudinal direction of the first exhaust treatment device is greater than a width of the first support portion in the first direction.
A work vehicle according to a second aspect of the present invention includes an engine, a vehicle body frame, a first exhaust treatment device, a second exhaust treatment device, a first bracket and a second bracket. The vehicle body frame includes a plurality of column members and a beam member. The plural column members are mounted upright onto a revolving frame supporting the engine. The beam member is mounted onto the upper ends of the column members. The first exhaust treatment device is configured to treat exhaust gas from the engine. The second exhaust treatment device is configured to treat the exhaust gas from the engine. The first exhaust treatment device and the second exhaust treatment device are attached to the first bracket. The second bracket supports the first bracket. The first bracket includes a brim part and a main body part. The main body part has a convex shape downwardly bulged from the brim part. The main body part includes a first support portion, a second support portion and a fourth attachment portion. The first support portion directly supports the first exhaust treatment device. The second support portion directly supports the second exhaust treatment device. The second bracket is attached to the fourth attachment portion. The second bracket includes a fifth attachment portion and a sixth attachment portion. The first bracket is attached to the fifth attachment portion. The sixth attachment portion is attached to the beam member.
The fifth attachment portion may be positioned below the beam member.
The sixth attachment portion may positioned above the fifth attachment portion.
The main body part may further includes a first attachment portion, which allows a hoist hook to be attached thereto, on a lateral surface thereof. In addition, the first attachment portion may be positioned above the beam member while the first bracket is attached to the second bracket.
The first attachment portion may be positioned above the sixth attachment portion while the first bracket is attached to the second bracket.
The aforementioned work vehicle may further include a third reinforcement plate. The third reinforcement plate is disposed between the fourth attachment portion and the fifth attachment portion on a surface of the main body part, which is opposite to the other surface of the main body part where the first exhaust treatment device and the second exhaust treatment device are supported.
The aforementioned work vehicle may further include a connection pipe connecting the engine and the first exhaust treatment device. In addition, the first exhaust treatment device and the second exhaust treatment device have cylindrical shapes. Furthermore, the connection pipe may extend in parallel to a plane including a center axis of the first exhaust treatment device and a center axis of the second exhaust treatment device.
An exhaust treatment unit according to a third aspect of the present invention is for treating exhaust gas from an engine of a work vehicle, and comprises a first bracket, a first exhaust treatment device and a second exhaust treatment device. The first bracket is formed by means of a first step and a second step. In the first step, a prototype bracket, including a brim part and a main body part, is formed by means of stamping of a single plate member. The main body part has a convex shape downwardly bulged from the brim part, and includes a first support portion and a second support portion. In the second step, a surrounding part of the brim part is cut out from the prototype bracket. The first exhaust treatment device is disposed immediately on the first support portion. The second exhaust treatment device is disposed immediately on the second support portion.
A method of manufacturing an exhaust treatment unit according to a fourth aspect of the present invention includes a first step, a second step, a third step and a fourth step. In the first step, a prototype bracket, including a brim part and a main body part, is formed by means of stamping of a single plate member. The main body part has a convex shape downwardly bulged from the brim part, and includes a first support portion and a second support portion. In the second step, a first bracket is formed by cutting out a surrounding part of the brim part from the prototype bracket. In the third step, the first exhaust treatment device is disposed immediately on the first support portion. In the fourth step, the second exhaust treatment device is disposed immediately on the second support portion.
In the exhaust treatment unit and the work vehicle of the present invention, the first support portion and the second support portion are integrally formed with the first bracket. Therefore, according to the exhaust treatment unit and the work vehicle, the diesel particulate filter device and the selective catalytic reduction device can be stably supported with a small number of components.